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Unlike "traditional" welding processes, laser welding is a method whereby highly-focused laser light is used
to generate a welding arc, rather than electricity or a combination of gasses.
Laser welding is a fusion process, where filler material is normally not added.
The welding is performed by a high energy density beam, where energy is targeted directly on the workpiece at the point of the weld.
Laser differs from both GTAW
(Gas Tungsten Arc Welding) and MIG (Metal Inert Gas) welding in that an
electrical circuit is not require through the workpiece.
There are two types of laser welding delivery systems. In one, the laser beam is
delivered to the workpiece through “hard optics,” or a series of mirrors and
lenses. One drawback of this method is the distance limitations between the
laser source and the workpiece.
The other laser delivery system utilizes a fiber optic cable to transmit the
laser beam to the workpiece. This method offers greater flexibility, as the beam
can be carried dozens of feet without losing significant energy. The laser is
then refocused onto the workpiece at the area to be welded. Laser welding also results in very strong, clean welds, because light is used as the heat source in this type of welding process.
In laser welding, the laser beam is focused on a targeted section of the workpiece being welded. At the surface of the workpiece, this focused light energy is converted into thermal energy at very high temperatures. Temperatures great enough to melt the metal being welded, but not so great as to vaporize it, as this would result in a hole or cut rather than a weld.
A major advantage of laser welding over other methods is the fact that a pulsed
laser introduces the minimal amount of heat required to perform the weld. By
pulsing repeatedly, the beam allows for an amount of cooling to occur between
each weld, keeping heat from building up on the workpiece. This makes laser
welding ideal for products that require welding near electonics or other
heat-sensitive components.
At the moment laser welding equipment is still relatively expensive, and cost prohibitive for most welding shops. As a result, this type of welding is not
usually performed outside of commercial or industrial settings.
